Global warming, mass shootings, global instability and overpopulation are all concerns humanity faces, but what is the greatest risk to all of us? Larry King asked scientific genius Stephen Hawking, who explained that there is a lot to be worried about.

Dear Dolphin Savers,
I hope you will tune in this Thursday (Thanksgiving Day) to Larry King on CNN, 8 PM Eastern / 5 PM Pacific. Actor Ben Stiller and I will be Larry's special guests to talk about the Save Japan Dolphins Campaign.